In theory, the repair of electronic apparatus or electronic circuits is simple; to wit, determine which part is bad or malfunctioning and simply replace it. In actual practice, what was once easy has become over the years difficult, expensive and unreliable. For example, there is involved either moving parts inventories to the defective electronic apparatus or moving the defective apparatus to an electronic workshop and back. Early proposals advocated the use of replaceable building blocks referred to as modules. However, the replacement of modules in present-day systems has to be carried out by trained electronic specialists and by persons having to carry large inventories of modules. Essentially, a "hit and miss" substitution method is undertaken all the while running the risk of carrying a bad module which was either improperly rebuilt or inadvertently replaced at one time.
As a result of the foregoing, the trend presently is to go back to the single, large, cheaply manufactured circuit board with its huge amount of soldered-in components. In other words, the trend is away from the expensive modular technology. This trend in turn nullifies the possibilities of efficient home repairs by even skilled repairers. Essentially, a consumer can do nothing service-wise under such circumstances.